Search results for "hell"
showing 10 items of 1035 documents
Determination of ion-induced K-shell ionization cross sections by comparison with nuclear Coulomb excitation
1979
Abstract A new method for the determination of cross sections for K-shell ionization of heavy atoms by charged particles is proposed. The method is based on a comparison of photon lines due to K X-rays and low-energy γ-rays, the latter ones being produced in nuclear Coulomb excitation with accurately known cross sections. This procedure applies within a limited energy range to the study of targets comprising deformed even nuclei, but can also be extended to other targets having Z≳30. A test of the new technique has been carried out for Gd, W, Th and U natural targets irradiated by 4.75 MeV protons. For Th, also energies of 6.80–10.10 MeV were used. The results are briefly discussed with ref…
Threshold Electroproduction of Charged Pions from Light Nuclei
1977
Double-differential cross sections for the electroproduction of pions of both charges have been measured. We compare the data obtained for production near threshold from $^{12}\mathrm{C}$ and $^{16}\mathrm{O}$ with theoretical treatments employing both shell-model and sum-rule nuclear descriptions with full inclusion of the final-state interaction.
New beta-decaying state in Bi-214
2021
13 pags., 7 figs., 3 tabs.
Electrons on a spherical surface: Physical properties and hollow spherical clusters
2012
We discuss the physical properties of a noninteracting electron gas constrained to a spherical surface. In particular we consider its chemical potentials, its ionization potential, and its electric static polarizability. All these properties are discussed analytically as functions of the number $N$ of electrons. The trends obtained with increasing $N$ are compared with those of the corresponding properties experimentally measured or theoretically evaluated for quasispherical hollow atomic and molecular clusters. Most of the properties investigated display similar trends, characterized by a prominence of shell effects. This leads to the definition of a scale-invariant distribution of magic n…
An RMHD study of transition between prompt and afterglow GRB phases
2008
We study the afterglow phases of a GRB through relativistic magnetohydrodynamic simulations. The evolution of a relativistic shell propagating into a homogeneous external medium is followed. We focus on the effect of the magnetization of the ejecta on the initial phases of the ejecta-external medium interaction. In particular we are studying the condition for the existence of a reverse shock into the ejecta, the timescale for the transfer of the energy from the shell to the shocked medium and the resulting multiwavelength light curves. To this end, we have developed a novel scheme to include non-thermal processeses which is coupled to the relativistic magnetohydrodynamic code MRGENESIS in o…
Isomers and high-spin structures in the N=81 isotones Xe135 and Ba137
2017
The high-spin structures of the N = 81 isotones 135Xe and 137Ba are investigated after multinucleontransfer (MNT) and fusion-evaporation reactions. Both nuclei are populated in (i) 136Xe+238U and (ii) 136Xe+208Pb MNT reactions employing the high-resolution Advanced Gamma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA, (iii), in the 136Xe+198Pt MNT reaction employing the -ray array GAMMASPHERE in combination with the gas detector array Chico, and (iv) via a 11B+130Te fusion-evaporation reaction. The high-spin level schemes of 135Xe and 137Ba are considerably extended to higher energies. The 2058-keV (19=2 ) state in 135Xe is identified as an isomer, completing the systema…
Lifetime measurements of excited states in neutron-rich Ti53 : Benchmarking effective shell-model interactions
2020
Level lifetimes of the yrast (5/2(-)) to 13/2(-) states in the neutron-rich nucleus Ti-53, produced in a multinucleon-transfer reaction, have been measured for the first time. The recoil distance Doppler-shift method was employed and lifetimes of the excited states were extracted by a lineshape analysis aided by GEANT4-based Monte-Carlo simulations. The experiment was performed at the Grand Accelerateur National d'Ions Lourds facility in Caen, France, by using the Advanced Gamma Tracking Array for the gamma-ray detection coupled to the large-acceptance variable mode spectrometer for an event-by-event particle identification and the Cologne plunger for deep-inelastic reactions. Reduced trans…
First Glimpse of the N=82 Shell Closure below Z=50 from Masses of Neutron-Rich Cadmium Isotopes and Isomers
2020
We probe the $N=82$ nuclear shell closure by mass measurements of neutron-rich cadmium isotopes with the ISOLTRAP spectrometer at ISOLDE-CERN. The new mass of $^{132}\mathrm{Cd}$ offers the first value of the $N=82$, two-neutron shell gap below $Z=50$ and confirms the phenomenon of mutually enhanced magicity at $^{132}\mathrm{Sn}$. Using the recently implemented phase-imaging ion-cyclotron-resonance method, the ordering of the low-lying isomers in $^{129}\mathrm{Cd}$ and their energies are determined. The new experimental findings are used to test large-scale shell-model, mean-field, and beyond-mean-field calculations, as well as the ab initio valence-space in-medium similarity renormalizat…
High-spin structure in the transitional nucleus Xe131 : Competitive neutron and proton alignment in the vicinity of the N=82 shell closure
2018
The transitional nucleus 131Xe is investigated after multinucleon transfer (MNT) in the 136Xe+208Pb and 136Xe+238U reactions employing the high-resolution Advanced GAmma Tracking Array (AGATA) coupled to the magnetic spectrometer PRISMA at the Laboratori Nazionali di Legnaro, Italy and as an elusive reaction product in the fusion-evaporation reaction 124Sn(11B,p3n) 131Xe employing the HORUS γ-ray array coupled to a double-sided silicon strip detector (DSSSD) at the University of Cologne, Germany. The level scheme of 131Xe is extended to 5 MeV. A pronounced backbending is observed at ~ω ≈ 0.4 MeV along the negative-parity one-quasiparticle νh11/2(α = −1/2) band. The results are compared to t…
Exchange and correlation energy functionals for two-dimensional open-shell systems
2009
We consider density functionals for exchange and correlation energies in two-dimensional systems. The functionals are constructed by making use of exact constraints for the angular averages of the corresponding exchange and correlation holes, respectively, and assuming proportionality between their characteristic sizes. The electron current and spin are explicitly taken into account, so that the resulting functionals are suitable to deal with systems exhibiting orbital currents and/or spin polarization. Our numerical results show that in finite systems the proposed functionals outperform the standard two-dimensional local spin-density approximation, still performing well also in the importa…